Dunkleosteus is an extinct genus of large arthrodire fish that existed during the Late Devonian period, about 382–358 million years ago. It consists of ten species, some of which are among the largest placoderms to have ever lived: D. terrelli, D. belgicus, D. denisoni, D. marsaisi, D. magnificus, D. missouriensis, D. newberryi, D. amblyodoratus, D. raveri, and D. tuderensis, and the largest and most well known species is D. terrelli. Since body shape is not known, various methods of estimation put the living total length of the largest known specimen between 4.1 to 10 m long and weigh around 1–4 t. Dunkleosteus could quickly open and close its jaw, like modern-day suction feeders, and had a bite force of 4,414–6,170 N at the tip and 5,363–7,495 N at the blade edge. Numerous fossils of the various species have been found in North America, Poland, Belgium, and Morocco. Dunkleosteus was a pelagic fish inhabiting open waters, and an apex predator of its ecosystem.
Dinichthys is an extinct monospecific genus of large marine arthrodire placoderm from the Late Devonian measuring around 3 metres (9.8 ft) long. Fossils were recovered from the Ohio Shale Formation along the Olentangy River in Delaware County, Ohio.
Bruntonichthys is an extinct monospecific genus of arthrodire placoderm from the Early Frasnian stage of the Late Devonian period. Fossils are found in the Gogo Formation of the Kimberley region of Australia. The skull is about 139 millimetres long, and had disproportionally large eye sockets. Researchers suggest it may have preyed on small mollusks.
Gorgonichthys is extinct monospecific genus of large arthrodire placoderm. Fossils are found in the Upper Famennian Cleveland Shales of Late Devonian in Ohio. The type species is Gorgonichthys clarki.
Mcnamaraspis is an extinct monospecific genus of arthrodire placoderm that inhabited the ancient reef system of north Western Australia during the Frasnian epoch of the Late Devonian period. The type specimen was found and described by John A. Long from the Gogo Formation near Fitzroy Crossing. This fossil fish showed new anatomical features in arthrodires, like the well-preserved annular (ring-shaped) cartilages of the snout, previously inferred to be present by Erik Stensiö of Sweden. It is occasionally referred to as "The Gogo Fish" after the locale the holotype was excavated from.
Stenosteus is an extinct monospecific genus of medium-sized selenosteid arthrodire placoderms of the Late Devonian period known from the Upper Famennian Cleveland Shale of Ohio. Estimated skull lengths range from 6 to 9 centimeters Most fossils of Stenosteus have been scraps of armor and portions of tooth-plates suggestive of Selenosteus. In 1996, enough material of a new species, S. angustopectus, was recovered to allow a reconstruction of armor that resembles that of Selenosteus.
Gymnotrachelus is an extinct monospecific genus of large selenosteid arthrodire placoderm of the Late Devonian known from the Late Famennian Cleveland Shale of Ohio. The type species Gymnotrachelus hydei was originally reconstructed as physically resembling Selenosteus, with slightly smaller orbits. Later specimens led to a reappraisal, and now G. hydei is thought to have a more gar-like or barracuda-like build.
Protitanichthys is an extinct genus of comparatively large coccosteid arthrodire placoderms from the Middle Devonian of the eastern United States. Fossils are found primarily in the Eifelian-epoch aged Delaware Limestone of Ohio, and the Lower Givetian-aged Rockport Quarry Limestone of Michigan
Coccosteidae is a family of arthrodire placoderms from the Early to Late Devonian. Fossils appear in various strata in Europe, North America and China.
Harrytoombsia is an extinct genus of arthrodire placoderm from the Early Frasnian stage of the Late Devonian period. Fossils are found from Kimberley, Australia. It was a fast-swimming predator, and it had sharp blades of enamel-like material around the outer edge of the jaw for catching prey.
Millerosteus is an extinct genus of coccosteid arthrodire placoderm from the Early Givetian stage of the Middle Devonian period. Fossils are found in the Orkneys and Caithness, Scotland. It was a small placoderm with an body length of 14 cm (5.5 in). Millerosteus is one of the few arthrodires known from specimens preserving the entire skeleton.
Dickosteus is an extinct genus of coccosteid arthrodire placoderm from the Late Eifelian to Early Givetian stages of the Middle Devonian period. Fossils are found in the Orkneys and Caithness, Scotland. It was a small placoderm with a total body length of 43.7–52.3 cm (17.2–20.6 in). It is one of the few placoderms for which complete bodies are known.
Watsonosteus is an extinct genus of coccosteid arthrodire placoderm from the Late Givetian stage of the Middle Devonian period. Fossils are found in the Orkney Islands, Scotland. It was a small placoderm with an total body length of 57 cm (22 in), with the largest individuals reaching lengths of 1 m (39 in). It is one of the few arthrodires for which complete body fossils are known.
Torosteus is an extinct genus of arthrodire placoderm from the Early Frasnian stage of the Late Devonian period. Fossils are found in the Kimberley region of Australia.
Trematosteus is an extinct monospecific genus of arthrodire placoderm from the Late Frasnian stage of the Late Devonian period. Fossils are found from Bad Wildungen, Germany.
Tapinosteus is an extinct monospecific genus of arthrodire placoderm from the Late Frasnian stage of the Late Devonian period. Fossils are found from Bad Wildungen, Germany.
Bullerichthys is an extinct monospecific genus of arthrodire placoderm from the Early Frasnian stage of the Late Devonian period. Fossils are found in the Gogo Formation of the Kimberley region of Australia. It was thought to be durophagous, meaning that it preyed upon hard-shelled creatures such as mollusks.
Kendrickichthys is an extinct monospecific genus of arthrodire placoderm from the Early Frasnian stage of the Late Devonian period. Fossils are found in the Gogo Formation of the Kimberley region of Australia. It was thought to be durophagous, meaning that it preyed upon hard-shelled creatures such as mollusks.
Brachyosteus is an extinct genus of arthrodire placoderm from the Late Frasnian stage of the Late Devonian period. Fossils are found from Bad Wildungen, Germany.
Amazichthys is an extinct genus of selenosteid arthrodire from the Middle Famennian of the Late Devonian of the Anti-Atlas Mountains of Morocco. It contains a single species, Amazichthys trinajsticae. It is one of a few example of placoderm known from whole body shape, including cartilaginous axial and fin elements.
